Drying of sheet material



1935- i G. A. SCHETTLER 2,000,991

DRYING 0F SHEET MATERIAL Filed Aug. 25, 1932 4 sheets sheet 1 y 1935 I cs. A.-SCHETTLER 2,000,991

DRYING OF SHEET MATERIAL Filed Aug. 25, 1932 4 Sheets-Sheet 2 May 14, 1935. e. A. SCHETTLER DRYING OF SHEET MATERIAL Filed Aug. '25, 1952 '4 Sheets-Sheet 3 y' 1.935- G. A. SCHETTLER 2,000,991

DRYING OF SHEET MATERIAL Filed Aug. 25, 1932 4 Shets-Slieet 4 Patented May 14, 1935 r 2,000,991

UNITED STATES PATENT OFFICE DRYING OF SHEET MATERIAL Gustav Adolf Schettler, Leeds, England, assignor to The Turner Tanning Machinery Company, Portland, Maine, a corporation of Maine Application August 25, 1932, Serial No. 630,343 In Great Britain September 4, 1931 16 .Claims. (Cl. 3428) This invention relates to the drying of sheet by a current of air passing'from marginal pormaterial. While the invention is described with tions toward central portions of the piece of reference to the drying of, that is, the removal work. Conveniently the piece of work is rotated of water from, hides and skins, it will be underabout a central axis while a current of air is stood that the invention and various important caused to flow in a direction at a right angle 5 characteristics and features thereof may have to the axis of rotation from marginal portions other applications and uses. of the piece of work to central portions thereof.

In accordance with one of the methods here- By this method the denser portions of the piece tofore commonly practiced in the drying of hides of work receive more treatment than the thinner and skins, each hide or skin was suspended in a and looser-textured marginal portions, since the 10 chamber through which heated air was circucentral por ions m v m re l wly and h nc related in large amounts. According to another main for a longer time within range of the curmethod the hides or skins were passed through rent of air. It follows that the central and martunnels by a conveyor mechanism, the tunnel beal p t of the hide Skin y in about ing heated to a relatively high temperature and the same time. That is, there is a close app'roxi 15' the hides or skins traveling through the tunnel mation to uniformity n the time r quired for suspended transversely of their direction of dry ng 80 t a Ov y 0f t e thinner and travel. In both of these cases tremendous 100Ser-teXtl1red parts is aVOided- Moreover, amounts of heated air were employed. in drying Since the p d for drying iS ed ced considerthe hides or skins with results not altogether ably the e is 11 heed o p y the gh tem- 20 satisfactory. In such mass treatment, individual Deretures heretofore used, Which t d to easepieces of work were not infrequently underdried harden he S ces of the hide or skin and rewhile other pieces were overdried. Furthermore, dllee e quality thereofy this method each there was no uniformity in the drying of different Pi e O Work receives the Same treatment as portions of the same hide or skin. In accordv ry th r piece so that t r s r at uniform- 25 ance with another method of drying hides'and ty i he p odu t. skins, each hide or skin was stretched upon a For Practicing the method described in h P frame and subjected to a drying operation by beceding p a aph there is p vid d, i h illusing suspended in a heated chamber or loft. Here, trated Construction. means for Presenting a Pi again, the results were more or less haphazard of W e eWiSetO a cu e t o a r s tha the 30 as far as individual pieces were concerned. letter ve from marginal Portions of the Pi Furthermore, there was a tremendous amount of Of W t Central Portions thereof in an Work in the handling of the heavy frames hereto- Zation wher in m an i also pr v d f r usfore commonly employed in stretching operations e s h re ve ve t between the P c preliminary to drying. of work and the current of moving air as to in- 35 It is an object, of this invention to s cure sure treatment of all portions of the piece of work greater uniformityin drying operations upon ou a p ve transfer of e e d o hides and skins, not only with respect to the treating operations in one direction around the difierent pieces undergoing treatment but a g a p o of the Piece Of k un a throughout all portions of each individual piece portions have been treated. Conveniently, means 40 of work. It is a further object of the invention is provided for rotating a piece of work about a to shorten the drying operation, to improve the central axis while a current of air restricted in product, and to reduce to a marked degree the width is caused to flow in a direction at a right amount of labor required. angle to the said axis and from the outeredge To these ends and in accordance with an imof the piece of work to central portions thereof 45, portant characteristic of the invention a currentPWhereby all marginal portions of the piece of of air is caused to travel over the surface of Ta work are treated-in'succession for relativelylim hide or skin from marginal portions thereof to ited pe o Offi hf 18? more central portions central portions of the hide or skin, difierent-of the piece of lwor I eive considerably'long'er 5 0 portions of the hide or. skin being presented to" treatment by the "said current of air passing over the air current through such relative movement the surface thereof, differences in duration of of the piece of work and of the moving airas treatment being due to differences in the rate of-" to transfer the field of treatment progressively travel of portions of the work at variousdistances around the margin of the piece of work until all from the axis 'of rotation. By reason of thisportions 'of the piece of work have been treated relative movement between the piece of work and 66 the current or currents of air, the various portions of the piece of work receive the amount of treatment suited to the requirements of each, it being clear that the thinner and looser textured marginal portions receive less treatment than the denser and thicker portions in the middle or central parts of the hide or skin. Furthermore, each hide or skin receives the same treatment individually as every other hide or skin, thus contributing markedly to uniformly good results in the product. By thus suiting the length of treatment to the various requirements of the different parts of the pieces of work, the drying operation is facilitated and may be terminated at exactly the right point, whereas according to methods heretofore practiced it was common to overtreat many pieces in order to insure that all of the pieces were subjected to sufficient treatment to secure drying thereof even though they were less favorably situated than those pieces which were dried first.

To facilitate presentation of the hides or skins edgewise to the drying current of air each hide or skin is mounted upon a drying frame which, in the illustrated construction, is circular in form.

, By reason of this circular shape the drying frame is not only handled with unusual ease by the laborer, since it may simply be rolled as a hoop -over the floor instead of being carried, but the circular shape also facilitates rotation of the drying frame and, therefore, of the piece of work attached thereto, while a current of air is passing over the surface of the piece of work. Due to the circular shape of the drying frame the mechanism for causing rotation thereof may be of the simplest construction. As illustrated, the means for causing rotation of the drying frames comprises two or more rotating members which serve also as supports for the drying frames while each frame rests upon its circular periphery, the rotation of the rollers serving to cause rotation of the circular drying frames, other means being provided to hold each frame in a vertical plane during its rotation.

While any one of several well-known means may be employed for causing air to flow in a direction at a right angle to the axis of rotation of the drying frames by which the air is caused tomove in a direction from marginal portions of each piece of work to central portions thereof, a preferred construction is that in which an air chamber is provided through which a body of air is caused to flow and to be discharged through openings in pairs one upon each side of one of the rotating drying frames. While the direction of the current of air may be varied greatly since it may be directed vertically or horizontally or at .any angle in between the vertical and the horiboth rollers serving to support a plurality of drying frames and to cause rotation thereof while the drying frames are supported in vertical positions by a plurality of racks, one located adjacent to each roller and another in or adjacent to a plane passing vertically through the axis of rotation of the drying frames. Through the provision of said racks it becomes a simple matter to introduce each drying frame simply by rolling it up a slight incline into position between the forks of the racks where it rests upon the said rollers.

These and other important characteristics and features of the invention and novel combinations of parts will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings,

Fig. 1 is a sectional end elevation of the machine, taken on line I-I of Fig. 3;

Fig. 2 is an end elevation of the machine as viewed from the left of Fig. 3;

Fig. 3 is a front elevation of the machine;

Fig. 4 is a front view of part of a rack employed in the machine and is drawn to a larger scale than the remaining figures;

Fig. 5 is a perspective view of a circular frame constituting such example;

Fig. 6 is a cross-sectional elevation of the central and peripheral portions of the frame, this figure being drawn to a larger scale than Fig. 5; and

Fig. 7 is view similar to Fig. 6 showing a frame provided with two work-supporting members.

In the illustrated embodiment of the invention designed particularly for use in the drying of hides and skins, there is provided a framework built up from angle and channel iron sections l, 2, 3, 4 and 5, and furnished with rollers 8 arranged in parallelism to each other from end to end of the framework, one at the base at the front, and ahother higher up near the back as shown in Fig. 1. The rollers. 6 are mounted in bearings I, the bearings for the lower roller being carried by plates 8 fixedly attached to the frame members 2 and 3, and the bearings for the upper roller 6 being carried by plates 9 attached to angle iron stays H), II, l2 fixedly secured to the main frame members. There are also provided parallel to the rollers 6 a plurality of racks l3 of a form adapted to provide a number of spaces or stalls I4 for the reception of the peripheral portions of drying frames l9. Conveniently I adopt racks of a form shown particularly in Fig. 4, i. e.-comprising a bar-like portion and a plurality of equally spaced integral tongues l5 forming between them the spaces or stalls I4 for the purpose aforesaid. Each of these racks l3 may consist of a single part or it may be made up of a number of sectionseach of the form shown in Fig. 4-arranged end to end as shown in Fig. 3 and suitably secured in position. The tongues or spacing members 15 are preferably tapered, as shown, in order to widen the entrances to the spaces or stalls I4 so as to facilitate entry of drying frames I9 when the machine is being loaded. Any suitable number of these racks l3 may be provided. Conveniently, and as shown in Figs. 1 and 3, there are three, one rack being arranged at the foot of the machine with its tongues or spacing members disposed upwards in the rear of the lower roller 6, another arranged just above the upper or back roller 6 with its tongues or spacing members disposed horizontally and projecting forwards, and the third rack arranged at the top of the machine frame with its tongues or spacing members disposed downwards. In the arrangement illustrated, the racks are fixedly attached to angle iron members l6 e. g. by means of rivets (although nut and bolt fastenings may be used instead) at the points l1. Also the members l6 may be connected to adjacent frame members, e. g. by means of angle brackets such as l8 suitably secured to the frame members. As will be perceived, the machine shown is adapted to support a single bank of drying frames l9, said frames, as shown in Figs. 1 and 3, being placed in the racks I3, i. c. with theirperipheries in the spaces or stalls I4, and resting-on the rollers 6, being thereby rotatably supported in an upright position and in the desired laterally spaced relation.

The machine is provided with an air chamber 20 having an inlet 2| and an outlet 22. Conveniently said chamber is formed by suitably applying sheet metal sections to the framework as indicated by thickened full lines at 23, 24 and 25 in Fig. 1, and by thickened dotted lines at 26 in Fig. 3. The ends of the frame may be closed by sheet metal sections 24a. A hood 2! is provided throughout the length of the machine. This hood may be formed partly by the front 25 of the aforesaid chamber 20, and partly by additional sections arranged on either side of the front 25. To form the hood the sheet metal sections may be applied to the stays l2 and additional inner stays |2a which, for this purpose, are curved as shown in Fig. 1, so as to extend upwards and forwards from the rear of the upper roller to the upper frame member 4 so that the sheet metal sections applied thereto form an upwardly and forwardly curving hood which partly covers the drying frames as represented in Fig. 1 when the frames are placed in the racks and on the rollers as hereinbefore described. The inner stays |2a may be attached to the upper frame member 4 and to a horizontal angle iron stay 28 in any usual manner, e. g. by rivets or nut and bolt fastenings. The outlet 22 is of course provided for the discharge of air from the chamber 20 in the direction of the bank of drying frames.- Conveniently this outlet is located at the lower end of the air chamber below the upper of the two rollers 6 and consists of concave metal plates formed with transverse slots or openings 29 and disposed parallel to the rollers 6 at an angle of about 45 degrees tothe horizontal, as shown in Fig. 1,

so that air is discharged from the air chamber 20 upwards, in a direction at right angles to the concave surface of theapertured or slotted plate, or substantially so, i. e. at an angle of from 45 to 60 degrees to the horizontal as represented by the arrows in Fig. 1. The concavity of the aforesaid surface corresponds to the curvature of the circular frames l9, and, as shown in Fig. 3, the plate is so arranged that, the slots or openings 29 therein alternate with the spaces or stalls l4 in which the drying frames are located, so that air discharged as aforesaid passes on op posite sides of each frame, when the frames are in position, i. e. it passes between the spaced frames so that it acts upon both sides of the material. A hide or skin 92 is attached to each frame as represented in Fig. 1, and since each drying frame is fitted with a perforated sheet work support, as will be hereinafter described, the hide or skin is exposed more or less on both sides. The outlet plate 22 may be attached to the stay 28 and to a similar member 30 similarly secured in the main framework.

The machine is furnished with a funnel or like casing 3| over the inlet 2| to the chamber 20 to contain a fan or blower 32 whereby air drawn from the atmosphere, either within the drying room or from outside, is drawn into and blown through the chamber as represented bythe arrows, and discharged through the outlet 22 as previously described herein. If the air is drawn from outside, steam coils or other heaters may be interposed at a convenient position for the purpose of reducing the humidity. Conveniently the funnel or casing 3| is welded or riveted to an annular support 33 mounted upon stays 34 riveted or otherwise secured to the upper part of the main framework. An air deflector 34 of sheet metal suitably shaped, e. g. curved transversely, may be provided longitudinally at the bottom of the air chamber 20 as shown in Fig. 1 for the purpose of directing the air to the outlet 22. Said deflector may be attached at one edge to the adjacent main framework and at the other edge to a bar 35 of wood suitably secured.

The fan or blower 32 may be driven in any suitable manner. In the illustrated arrangement, the fan shaft 36 is rotatably mounted vertically in a bearing 31 fixed by nut and bolt fastenings to the annular support 33, and is driven from a horizontal shaft 38 by means of mitre or bevel gearing 39, 40. The shaft 38 is mounted in bearings 4|, 42, one mounted on the support 33 and the other on top of the main framework at one end of the latter as shown in Fig. 3. The shaft 38 is driven by means of a belt (not shown) from a line shaft or some other suitable source of power, said shaft having a fast pulley 43 and a lose pulley 44 thereon, and a device 45 being provided for shifting the belt between said pulleys.

As will be understood, the rollers 6 are driven for the purpose of revolving the drying frames I9 in relation to the air outlet 22, and any suitable gearing may be provided for this purpose, the frames being revolved by reason of the frictional peripheral contact between the rollers and the frames. According to the construction illustrated, the rollers 6 are driven from the fan driving shaft 38 through the medium of reduction gearing and chain and sprocket gearing. To this end I provide on top of the main framework parallel to the shaft 38 a countershaft 46 furnished with a gear wheel 41 and 1a sprocket wheel 48, and an intermediate shaft 49 (Fig. 2) furnished with a pinion 50 and a gear wheel 5|. A pinion 52 is provided on the horizontal shaft 38. The pinion 52 meshes with the gear wheel 5|, and the pinion 50 meshes with the gear wheel 41. The upper of the two rollers 6 is provided with a sprocket wheel 53 (Figs. 1 and 3) and the other roller is provided with a similar sprocket wheel 54, and a chain 55 is passed round these sprockets and the sprocket 48 on the countershaft 46. By these means, when the main shaft 38 is driven, the drive is transmitted to the rollers 6 through the reduction gearing and the chain and sprocket gearing as indicated by arrows shown in Fig. 2, and the drying frames are revolved slowly in relation to the air discharging arrangement 22, in the direction of the arrows shown in Figs. 1 and 2. As will be understood, the countershaft 46 and the intermediate shaft 49 are mounted in suitable bearings fixed upon the upper part of the framework adjacent to the bearing 42.

The construction and arrangement of the various parts of the machine or apparatus described is such that circular frames l9, to which skins or other pieces of material to be dried are attached, can be rolled into position in the spaces or stalls l4 and on to the rollers 6. An inclined platform 51 is preferably provided in front of the lower roller 6 to facilitate the rolling of the frames into position. This platform may have rests 58 formed with notches 59 to fit upon an angle iron member 60 suitably fixed in the framework to prevent displacement of the platform.

As illustrated in Figs. 5 and 6, each stretching frame is of circular outline and comprises a circumferential rim l and an inner work supporting member 12. The rim 10 consists of a ring or hoop of metal of T-shaped section one portion 14 of which forms the periphery of the frame, upon which the latter can be rolled about. The circular T-shaped rim serves effectively to resist stresses and strains imposed by the drying hides or skins, thus making it possible to maintain the mass of material in the drying frame at a minimum. The central web of the said T-shaped piece is disposed inwards and thus constitutes a flange 16 around the inside of the rim for the attachment of the work supporting member 12. As shown, member 12 consists of a perforated circular sheet of metal, it being understood that other suitable constructions might be used such as expanded metal, wire netting or other foraminous sheet material attached in a suitable manner, e. g. by rivets, to the said internal flange 16 of the ring.

In the illustrated construction, the outer or peripheral part 14 of the metal ring is parallel to the axis of rotation of the circular frame l9 and the internal flange I6 is at right angles to said axis.

Conveniently the rim 10 is made from an-initially straight length of T iron bent to circular form so that its ends abut, and the perforated member 12 comprises two semi-circular sections of sheet metal having perforations l8 comparatively closely spaced, and cut so that when applied to the web or flange 16 of the rim 10 one section overlaps the other. As shown, one of the semi-circular sections may have its straight edge offset to an extent equal to the thickness of the metal so as to provide a marginal portion 80 whereby when the two sections are applied to the web or flange I6, one section overlaps the other substantially as shown in Fig. 3. Conveniently I use sheet iron of about 18 gage U. S. standard, for plate perforated with holes and galvanized, the holes being spaced at say A" apart in a horizontal direction and 1 5" apart in a vertical direction. The two sections are secured circumferentially to the web or flange 16 by means of iron rivets 82, and to each other along their straight edges conveniently by means of copper rivets 84 suitably spaced, although any other suitable means may be adopted. Instead of making the member 12 of the frame IQ of two semi-circular sections as aforesaid, a single circular member may be used and secured peripherally to the web or flange 16 as aforesaid. The abutting ends of the rim Ill may be secured together e. g. by welding, or in some other suitable manner, or the attachment of the member 12 to the flange 16 may be relied upon to hold the two ends of the rim together.

As will be observed, in the construction illustrated in Figs. 5 and 6, the member 12 of the frame is constituted by material applied to one side only of the web or flange 16. However, Fig. 7 illustrates work supporting members 90 applied to both sides of the web or flange l6 and secured by the same rivets, or other means as previously mentioned herein, so that material to be dried or treated may be readily applied to both sides of the frame I9, especially where as here shown the members 90 are reticulated or perforated sheets, since the latter would form between them an air space to which, in the case of drying by air currents, the air would have access through the reticulations or perforations and so be able to act to some extent upon the back of the material to be dried in addition to acting upon the fully exposed front surfaces thereof.

While the improved frame herein described is mainly intended for use in drying operations, it may also be used for other operations where the skin, leather or other material is treated under tension, such for example as doping, enamelling, japanning and the like.

In Fig. 5, 92 represents a skin or like piece of material applied to one side of the improved frame and strained by means of clips 94, said clips being hooked into or otherwise engaged with perforations I8 in the work supporting member 12 of the frame. When the member 12 is not perforated but penetrable, e. g. when made of plywood or wood pulp such as beaver board, the skin or other piece of material may be secured by nails, tacking pegs or by means of clips furnished with spikes or the like driven into the said inner portion.

As shown in Figs. 1 and 2, the major portion of each frame IQ of the bank of drying frames is contained in a compartment formed by the closed ends of the framework and the hood 25 so that the air discharged from the outlet 22 is concentrated upon the bank of frames l9 until it has been blown beyond the center of rotation as previously set forth herein, the said hood serving properly to direct air blown upwards at an angle as aforesaid through the spaces between the drying frames; that is to say,useless dissipation of the air is prevented.

The aforesaid concave plates 22 may be regarded as gratings or grids which when the machine is loaded are located more or less below and on the inside of the center of the bank of frames, viewing the latter from one end i. e. as shown in Fig. 1. When, after the machine has been loaded with frames IS, the fan and the rollers are started, air is discharged under pressure from the aforesaid chamber 20 through the gratings or grids and directed outwards and upwards at an angle to the horizontal as aforesaid, so that while the frames l9 are rotated i. e. on an axis coincident with their centers, ,the air is blown diametrically across the frames through the spaces between the frames. Actually the air current is of such a strength as to extend from the gratings or grids to a point somewhat beyond the center of rotation so that the current deflnitely covers the skins or pieces of material from the edges to the centers and this, in conjunction with the rotation of the skins or pieces of material, ensures that each piece is adequately subjected to the drying effect of the air.

It will be understood that the framework is constructed so that any one or more of the frames may be withdrawn and replaced at any time without interfering with any of the remaining frames.

When frames l9 have been removed from the machine and the material thereon has been detached therefrom, they may be either replaced or they may be piled or stacked in a horizontal position elsewhere. Obviously the frames may be of any suitable diameter and may be spaced at any suitable distance apart.

I may provide a drying machine of such dimensions that when the last frame I9 is placed in position the first frame is ready to be removed and replaced by another frame carrying damp or wet material. In such case, instead of single rollers 6 there may be a plurality of sets of rollers, i. e. rollers such as 6 arranged end to end, the racks l3 being correspondingly extended.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent of the United States is:

1. That improvement in methods of drying hides, skins, and leather which comprises arranging each hide, skin or piece of leather in a plane or fiat condition, directing a current of air edgewise to the hide, skin or piece of leather so that it moves over a surface of the recited work piece from a marginal portion to central portions thereof, and causing relative rotative movement between said work piece and the current of air about the center of said work piece to treat progressively all portions of the work piece, whereby marginal portions of the hide, skin or piece of leather receive treatment for a shorter period of time than central portions thereof.

2. That improvement in methods of drying hides, skins, and leather which comprises arranging each piece of leather in a plane or fiat condition, directing a current of air edgewise to the piece of leather so that it moves over a surface of the leather from a marginal portion to central portions thereof, and rotating the piece of leather and maintaining the air current in action so as to expose marginal portions of the leather progressively to the action of the current of air whereby extreme marginal portions of the piece of leather are successively treated for limited periods of time while central portions of the same piece of leather receive considerably longer treatment by the air current.

3. In a machine for use in drying of hides, skins, leather and other similar pieces of work, means to produce a current of air, means to support a piece of work in a fiat condition and in a substantially vertical plane with the current of air flowing in a direction edgewise to the piece of work and in a path across a surface of the work, and means to cause relative rotation between the piece of work and the current of air while maintaining the flow of air edgewise to the work, whereby marginal portions of the piece of Work are progressively treated and for a relatively limited time while central portions of the work receive considerably longer treatment by the currents of air.

4. In a machine for use in drying of hides, skins, leather and other similar pieces of Work, a plurality of drying frames upon each of which a piece of work may be supported in flat condition, means to support the drying frames coaxially in vertical planes and in spaced relation to each other, means to rotate said drying frames, and means to cause currents of air to flow in a direction transverse to the axis of rotation of the drying frames, whereby both central and marginal portions of each piece of work are pro-- gressively subjected to the drying action of the air currents.

5. In a machine for use in drying hides, skins, leatherand other similar pieces of work, a frame to support each piece of work in a fiat condition, means to supporteach frame in a vertical plane, means to rotate each frame and piece of work in its own plane, and means to cause a current of air to flow in an edgewise direction with respect to each piece of work so that the air passes from marginal portions of the piece of work to is being rotated.

6. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a circular frame upon which a piece of work may be supported in fiat condition, means arranged to engage the periphery of said circular frame to rotate the latter, and means to produce currents of air flowing in a direction transverse to the axis of rotation of the frame, whereby the piece of work is progressively treated by said currents of air.

'7. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a circular frame upon which a piece of work may be spread out in flat condition, means comprising rotary members for supporting the circular frame in a vertical plane and for causing rotation of the latter in its own plane, and means arranged to direct currents of air transversely of the axis of rotation of the piece of work, whereby both marginal and central portions of the piece of work are progressively exposed to the air until 'all portions of the piece of work have been treated.

8. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of drying frames upon each of which a piece of Work may be spread out in flat condition, means to support the drying frames side by side in a horizontal row in spaced relation to each other, arranged to cause rotation of the frames each in its own plane, and means com-' prising a series of air discharging orifices arranged to direct currents of air in a direction edgewise with respect to the pieces of work during rotation of the latter whereby air currents are caused to flow from a marginal portion of each piece of work toward central portions thereof until all portions of the piece of work have been treated. v

9. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of frames each circular in form and each adapted to support a piece of work in flat condition, means arranged to maintain the frames each its own vertical plane, a pair of rollers spaced with respect to each other and arranged to support the frames, means to rotate the rollers whereby the frames are caused to rotate each in its own plane, and means to cause currents of air to flow in an edgewise direction with respect to each piece of work during rotation of the latter.

10. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of circular frames each adapted to support a piece of work in flat condition, a plurality of spaced members arranged to maintain the circular frames each in its own vertical plane, a plurality of rollers for supporting the circular frames, means to rotate the rollers thereby to cause rotation of the circular frames, and means to cause currents of air to flow in a direction at a right angle to the axis of rotation of the ciredgewise direction over the surface of each piece of work from marginal portions thereof to central portions thereof during rotation of each piece of work.

11. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of drying frames each circular in form and each adapted to support a piece of work in flat condition, a pair of rollers spaced with respect to each other and arranged to furnish the sole support for the drying frames, means to rotate the rollers whereby the drying frames are caused to rotate each in its own plane, racks arranged to maintain the circular frames in position during their rotation, and an air duct having orifices for directing air currents into the spaces between the drying frames during rotation of the latter, whereby each piece of work is progressively treated by the currents of air.

12. In a machine for min drying of hides, skins, leather and other similar pieces of work, a plurality of drying frames each adapted to support a piece of work in flat condition, means arranged to support the frames side by side each.

in its own vertical plane, means to rotate the frames about a common horizontal axis, and means comprising air passageways inclined upwardly at an angle of approximately 45 to the horizontal to cause currents of air to flow in an upward direction toward the front of the machine and at a right angle to the axis of rotation of the frames and radially across the surface of the frames, whereby both marginal and central portions of each piece of workare progressively subjected to the drying action of the air currents.

13. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of drying frames each adapted to support a piece of work in flat condition, means arranged to maintain the drying frames each in its own vertical plane, means to rotate the drying frames each in its own plane, and an air chamber having openings in pairs one upon each side of a drying frame and arranged to cause currents of air to flow in an edgewise direction with respect to each piece of work from marginal portions of the latter to the central portion of the piece of work.

. 14. In a machine for use in drying of hides, skins, leather and other similar pieces of work, a plurality of drying frames each circular in form and each adapted to support a piece of work in flat condition, means arranged to maintain the' drying frames each in its own vertical plane, a pair of rollers spaced with respect to each other and arranged to support the frames, means to rotate the rollers whereby the drying frames are caused to rotate each in its own plane, and an air chamber having openings in pairs one upon a each side of a drying frame and arranged to cause currents of air to flow in an edgewise direction with respect to each piece of work from marginal portions of the latter to the central portion of the piece of work.

15. A frame for supporting hides or skins during drying thereof comprising a circular rim T- shaped in cross section to provide both a cylindrical surface upon which the frame may be rolled and an annular flange inside of said cylindrical surface, and a member secured to said flange and adapted to afford support for a hide or skin spread out thereon, said circular T- shaped frame serving to withstand stresses and strains imposed by the drying hides or skins, whereby the mass of material in the frame may be maintained at a minimum, in combination with means for holding and stretching a hide or skin on the frame, means for blowing unsaturated air over the hide or skin for drying thereof,

' and means for rotating the frame while blowing the air over said. hide or skin.

16. A frame for supporting hides or skins d ing drying thereof comprising a circular rim T- shaped in cross section to provide'both a cylindrical surface upon which the frame may be rolled and an annular flange inside of said cylindrical surface, and members secured one to each side of said flange and in spaced relation to each other, the said members each comprising a sheet of foraminous material adapted to afford support for a hide or skin spread out thereon,

said circular T-shaped frame serving to withstand stresses and strains imposed by the drying hides or skins, whereby the mass of material in the frame may be maintained at a minimum, in combination with means for holding and stretching a hide or skin on the frame, means for blowing unsaturated air overthe hide or skin for drying thereof, and means for rotating the frame while blowing .the air over said hide or skin.

GUSTAV ADOLF SCHE'I'I'LER. 

